JP2006187178A - Motor with reducer mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor with a reducer mechanism for improving accuracy of bearing and enhancing a bearing holding load when a bearing arranged at the intermediate portion of an armature shaft is force-fitted. <P>SOLUTION: A yoke 11 for storing an armature 30, and a gear case 20 joined with the yoke 11 for storing a reducer mechanism S are provided which decelerates the rotation of the armature 30. At both ends of an axial hole 21 formed at the gear case 20, an intermediate portion 31c and one end 31a of the armature shaft 31 is rotatably supported through a pair of bearings 14, 15, while the other end 31b of the armature shaft 31 is rotatably supported through a bearing 13 engaged with a tube 11c having the bottom of the yoke 11 in the motor 10 with the reducer mechanism. A thin cylindrical bearing holder 22 is formed by drilling a cylindrical slit 23 on the side of opening 21c of the axial hole 21 at the gear case 20, and a bearing 14 for rotatably supporting the intermediate portion 31c of the armature shaft 31 is force-fitted in the bearing holder 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor with a speed reduction mechanism suitable for use in, for example, a power window motor or a wiper motor of an automobile.

  As this type of motor with a speed reduction mechanism, there is one shown in FIG. 4 (see, for example, Patent Document 1).

  As shown in FIG. 4, the motor 1 with a speed reduction mechanism is fastened to a substantially cylindrical yoke (motor case) 2 having an open end, and a flange portion 2 a around the open end of the yoke 2 via a screw 3. A fixed gear case 4 is provided. The armature shaft 7 of the armature 6 is rotated by the bearing 5a fitted to the bottomed cylindrical portion 2b at the other end of the yoke 2 and the bearings 5b and 5c fitted by press fitting in the vicinity of both ends of the shaft hole 4a of the gear case 4. It is supported freely.

  A worm 7 a is formed near one end of the armature shaft 7. Further, the gear case 4 is formed with a concave reduction mechanism housing portion 4b communicating with the shaft hole 4a. A worm wheel 8 that meshes with the worm 7a of the armature shaft 7 is rotatably supported in the speed reduction mechanism housing 4b. An output shaft 9 is fixed at the center of the worm wheel 8. The worm 7a and the worm wheel 8 constitute a speed reduction mechanism S that decelerates the rotation of the armature shaft 7.

JP 2002-136049 A

  However, in the conventional motor 1 with a speed reduction mechanism, the long armature shaft 7 is rotatably supported by the three bearings 5a, 5b, and 5c, so that the bearing 5b positioned in the middle portion of the armature shaft 7 and It is necessary to improve the accuracy of the shaft hole 4a of the gear case 4 into which the bearing 5b is press-fitted on the open end 4c side. In order to improve the accuracy of the bearing 5b located in the middle, the forming pin for forming the shaft hole 4a of the gear case 4 has been deformed and the accuracy thereof has been adjusted. The bearing holding load in the shaft hole 4a was reduced, and it was difficult to ensure stable accuracy over time.

  Therefore, the present invention has been made to solve the above-described problems, and can increase the bearing holding load when the bearing disposed in the intermediate portion of the armature shaft is press-fitted and improve the accuracy of the bearing. It is an object of the present invention to provide a motor with a speed reduction mechanism that can reliably prevent generation of vibration sound of an armature shaft.

  The invention of claim 1 includes a motor case that houses an armature that rotates when energized, and a gear case that is connected to the motor case and houses a reduction mechanism that decelerates the rotation of the armature. A shaft formed in the gear case A speed reducer that rotatably supports an intermediate portion and one end of an armature shaft through a pair of bearings at both ends of the hole and rotatably supports the other end of the armature shaft through a bearing attached to the motor case. In the motor with a mechanism, a thin cylindrical bearing holding portion is formed on the opening side of the shaft hole in the gear case, and a bearing that rotatably supports the intermediate portion of the armature shaft is press-fitted into the cylindrical bearing holding portion. It is characterized by.

  The invention according to claim 2 is the motor with a speed reduction mechanism according to claim 1, wherein an annular slit is formed in the gear case near the opening side of the shaft hole to form the thin cylindrical bearing holding portion. It is characterized by that.

  As described above, according to the first aspect of the present invention, the thin cylindrical bearing holding portion is formed on the opening side of the shaft hole in the gear case, and the intermediate portion of the armature shaft is rotated in the thin cylindrical bearing holding portion. By press-fitting the freely supported bearing, it is possible to increase the bearing holding load when the intermediate bearing is press-fitted and to improve the accuracy of the bearing. As a result, the stress applied to the intermediate bearing can be kept constant, and the generation of vibration noise of the armature shaft can be reliably prevented.

  According to the second aspect of the present invention, an annular slit is formed in the gear case in the vicinity of the opening side of the shaft hole to form a thin cylindrical bearing holding portion. Whatever the shape, the stable bearing accuracy can be ensured at all times, and the stress applied to the bearing can always be kept constant.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view showing a motor with a speed reduction mechanism according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a gear case used for the motor with the speed reduction mechanism, and FIG. 3 is a front view of the gear case.

  As shown in FIG. 1, a motor 10 with a speed reduction mechanism includes a substantially cylindrical yoke (motor case) 11 that is open on one end side, and a gear case made of synthetic resin that is fitted and fixed in the open end 11 a of the yoke 11. 20.

  A pair of magnets 12 are fixed to the inner peripheral surface 11b of the yoke 11 with an adhesive or the like. A bearing (bearing) 13 fitted to the bottomed cylindrical portion 11c at the other end of the yoke 11 and a pair of bearings (bearings) 14 and 15 fitted near both ends of the shaft hole 21 of the gear case 20 The armature shaft 31 is rotatably supported.

  As shown in FIG. 1, the armature shaft 31 has a worm 32 formed in the vicinity of one end 31a thereof. A recess (not shown) for housing half of the steel ball 33a is formed at the center of the end face of the other end 31b of the armature shaft 31. The steel ball 33 a is in contact with the bearing plate 16 fitted and fixed to the bottomed cylindrical portion 11 c of the yoke 11. Further, a recess (not shown) for accommodating half of the steel ball 33a is formed at the center of the end surface of the one end 31a of the armature shaft 31. The steel ball 33 a is in contact with the bearing plate 17 disposed on the bottom side of the shaft hole 21 of the gear case 20.

  An armature 30 is attached to a position of the armature shaft 31 facing the pair of magnets 12 and 12. The armature 30 is composed of an armature core 30a fixed to the armature shaft 31 and having a coil winding portion having a predetermined number of slots, and an armature coil 30b wound around the coil winding portion of the armature core 30a. Yes.

  Further, a commutator 34 is fixed at a position facing the boundary between the yoke 11 of the armature shaft 31 and the gear case 20. The commutator 34 includes the same number of commutator pieces 34a as the coil winding portion of the armature core 30a, and each commutator piece 34a and the armature coil 30b are electrically connected to each other.

  Further, the opening end of the shaft hole 21 of the gear case 20 is a large diameter hole 21a, and a pair of brushes 36, 36 are interposed via a holder 35 at a position facing the commutator 34 in the large diameter hole 21a. Is attached so as to contact the commutator piece 34a. Each brush 36 is electrically connected to a motor control circuit (not shown). Under the control of the motor control circuit, a current flows through the armature 30 or the like so that the armature shaft 31 rotates forward and backward.

  As shown in FIGS. 1 and 2, a shaft hole 21 is formed in the approximate center of the gear case 20, and a concave reduction mechanism housing portion 21d is formed in communication with the small-diameter hole portion 21b of the shaft hole 21. is there. A worm wheel 37 that meshes with the worm 32 of the armature shaft 31 is rotatably supported in the speed reduction mechanism housing portion 21d. An output shaft 38 is fixed at the center of the worm wheel 37. The worm 32 and the worm wheel 37 constitute a deceleration mechanism S that decelerates the rotation of the armature shaft 31 of the armature 30.

  As shown in FIGS. 1 to 3, an annular slit 23 is formed in the gear case 20 in the vicinity of the opening 21 c side of the small-diameter hole portion 21 b of the shaft hole 21 to form a thin cylindrical bearing holding portion 22. It is. The inner peripheral surface 22 a of the cylindrical bearing holding portion 22 is formed to have a larger diameter than the inner peripheral surface of the small diameter hole portion 21 b of the shaft hole 21. A tapered surface 22 b is formed on the opening side of the inner peripheral surface 22 a of the cylindrical bearing holding portion 22. A bearing (intermediate bearing) 14 that rotatably supports the intermediate portion 31c of the armature shaft 31 is fitted into the inner peripheral surface 22a of the cylindrical bearing holding portion 22 by press-fitting.

  According to the motor 10 with the speed reduction mechanism of the above embodiment, the thin cylindrical bearing holding portion 22 is formed in the gear case 20 near the opening 21c side of the shaft hole 21, and the inner peripheral surface 22a of the cylindrical bearing holding portion 22 is formed. Since the intermediate bearing 14 that rotatably supports the intermediate portion 31c of the armature shaft 31 is press-fitted to the armature shaft 31, when the intermediate bearing 14 is press-fitted, the bearing holding load of the cylindrical bearing holding portion 22 can be increased. In addition, the accuracy of the bearing 14 can be improved. Thereby, the stress applied to the intermediate bearing 14 can be kept constant, and the generation of vibration noise during the rotation of the armature shaft 31 can be reliably prevented.

  Further, by forming an annular slit 23 in the gear case 20 in the vicinity of the opening 21c side of the shaft hole 21 to form a thin cylindrical bearing holding portion 22, an outer side of the cylindrical bearing holding portion 22 is formed. Regardless of the shape, it is possible to always ensure the accuracy of the intermediate bearing 14 by the simple operation of forming the annular slit 23, and the stress applied to the intermediate bearing 14 is always constant. Can be held in.

  In addition, according to the said embodiment, although the depth of the slit was formed a little deeper than the width | variety of an intermediate bearing, you may form in the same depth as the width of a bearing.

It is sectional drawing which shows the motor with a reduction mechanism of one Embodiment of this invention. It is sectional drawing of the gear case used for the said motor with a reduction mechanism. It is the said gear case front view. It is sectional drawing of the conventional motor with a reduction mechanism.

Explanation of symbols

10 Motor with reduction mechanism 11 Yoke (motor case)
13 Bearing
14,15 A pair of bearings (bearings)
20 gear case 21 shaft hole 21c opening 22 cylindrical bearing holding portion 23 annular slit 30 armature 31 armature shaft 31a one end 31b other end 31c intermediate portion S speed reduction mechanism

Claims (2)

A motor case that houses an armature that rotates when energized, and a gear case that is connected to the motor case and houses a reduction mechanism that decelerates the rotation of the armature, and a pair of bearings at both ends of a shaft hole formed in the gear case In the motor with a speed reduction mechanism that rotatably supports the intermediate portion and one end of the armature shaft via the bearing, and the other end of the armature shaft is rotatably supported via a bearing attached to the motor case.
A reduction gear characterized in that a thin cylindrical bearing holding portion is formed on an opening side of a shaft hole in the gear case, and a bearing that rotatably supports an intermediate portion of the armature shaft is press-fitted into the cylindrical bearing holding portion. Motor with mechanism. A motor with a speed reduction mechanism according to claim 1,
A motor with a speed reduction mechanism, characterized in that an annular slit is formed in the gear case near the opening side of the shaft hole to form the thin cylindrical bearing holding portion.

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